This invention relates to switching systems and more particularly to a switching method and apparatus for selectively connecting one of a group of similar devices to a common bus or the like.
In situations where it is necessary to compare the performance of a number of alternative components of a system it is essential to have the ability to insert and remove components in the system quickly and easily. In audio showrooms, for example, it is necessary to demonstrate a variety of alternative components in an audio system and to switch back and forth between alternative components. A basic audio system will usually include a phonograph, a tape deck, an amplifier and at least one speaker. The switching requirements for demonstrating a number of one type of component are significant and increase rapidly when several types of components are demonstrated.
It has been customary to use centralized switching for making the various component substitutions in audio applications and in other fields as well. Wiring is thus provided from each speaker to a speaker switching center, from each amplifier to an amplifier switching center, from each phonograph to a phonograph switching center and so forth. Connections from the selected phonograph to the selected amplifier and from there to the selected speaker are made by jumper wires, or in some cases, through relay contacts. The disadvantages of such a system are apparent, both visually and performance-wise. Heavy bundles of wires overlap and criss-cross in various paths behind walls and counters in audio showrooms. The volume of wires makes the wiring susceptible to noise pickup and cross-talk and limits the number of component combinations that can be demonstrated.